DeKALB – Residents are advised to dress warm or stay indoors as the region braces today for the lowest temperatures of the winter season.

Temperatures that hung in the single digits Monday afternoon were expected to drop to 4 below zero overnight. But factoring in wind gusts, wind chills of between minus-25 and minus-15 degrees are expected.

A wind chill advisory from the National Weather Service was in effect from 6 p.m. Monday to 9 a.m. today. Much of the Midwest is covered by either a wind chill advisory or warning.

National Weather Service meteorologist Amy Seeley said this has been the coldest part of the season.

“If you have to go outside, dress appropriately with a hat and gloves,” Seeley said. “If you don’t have to be outside, don’t.”

Dr. Andrew Oleksyn, director of the emergency department at Kishwaukee Community Hospital in DeKalb, said people should avoid prolonged exposure to the cold weather. He advised people to wear multiple layers of loose, dry clothing if they must be outside.

A person who does not take these precautions risks hypothermia, Oleksyn said.

“Take a thermometer ... if [your body temperature] is below 95 degrees, it’s considered an emergency and you should seek medical attention,” Oleksyn said.

Hypothermia can occur at any temperature, he said.

Jon Bockman, owner of Bockman’s Auto Care at 2158 Oakland Drive, Sycamore, recommended that drivers store their vehicles in a garage overnight. If that’s not possible, Bockman said parking the car in a location sheltered from the wind could help.

Below-zero temperatures can affect a car in several ways, Bockman said, but there are a number of steps drivers can take to minimize the impact, including checking the antifreeze and tire pressure. Tire pressure can drop as cold temperatures cause the air inside tires to contract.

“If you hit a pothole, you can blow a tire,” he said.

Superintendent Jim Briscoe of DeKalb School District 428 said he has spoken with the transportation director and others about preparations for school today. In addition to checking on the buses, Briscoe said he has spoken to maintenance about making sure the buildings are heated well.

“There are never any guarantees when the temperatures drop,” Briscoe said.

Briscoe advised parents to make sure their children are covered before they leave the house.

“People need to dress appropriately,” Briscoe said. “Don’t let their kids leave until they do so.”